In the case of bipolar transistors formed in an integrated circuit (IC) where the base of the transistor is contacted through a contact on the surface of the IC, the base typically includes one or two extrinsic base regions, as illustrated in FIG. 1. The typical BJT 100 shown in FIG. 1 includes an emitter 102 contacted by emitter metal 104, a base 106 with extrinsic base regions 108, and a collector 110. The BJT 100 is isolated from surrounding structures by isolation regions 112. The extended extrinsic base regions 108 however form a large junction area with the collector 110, which results in significant parasitic capacitance between the extrinsic base regions 108 and the collector 110. For convenience, this is simply referred to as the base-collector capacitance. It will be appreciated that the parasitic capacitance has a significant effect on fMax (the maximum frequency at which the device can practically be operated) and fT (the cut-off frequency where voltage gain is unity). It would therefore be desirable to be able to increase fMax and fT.